1. Field of the Invention
The present invention relates to a lens barrel for holding multiple lenses, and more particularly relates to a lens barrel that enables easy alignment between lenses (adjustment to align the optical centers).
2. Description of the Related Art
As to photographing apparatuses such as digital cameras, there has recently been a demand for higher image quality of photographed images. To meet the demand for higher image quality, it has been considered to increase the number of lenses used in an optical system. Here, to meet the demand for higher image quality, so-called alignment between lenses needs to be accurately performed in the lens barrel, i.e., the positions of the respective lenses when viewed orthogonal to the photographing optical axis of the optical system need to be set to predetermined positions according to the settings for the optical system.
To this end, there has been known a lens barrel having a configuration in which a lens tube is provided with three alignment pins for enabling adjustment of a supporting position when viewed orthogonal to the photographing optical axis, and supports an annular part holding an objective lens by using the three alignment pins (see Japanese Patent Application Publication No. 2007-139947). By appropriately adjusting the supporting position with the three alignment pins, the lens barrel can adjust the position of the annular part relative to the lens tube, i.e., the position of the objective lens in the direction orthogonal to the photographing optical axis relative to other lenses held by the lens tube.
However, since the conventional lens barrel described above has the configuration in which the annular part holding the objective lens is supported by the three alignment pins so as to be movable relative to the lens tube, a gap is generated between the lens tube and the annular part at areas other than the three support points. This gap may allow dust to enter between the objective lens and the other lenses held by the lens tube. Such dust impairs the appearance quality of the lens barrel (particularly, the objective lens), and causes a shadow on a captured image, thus impairing the image quality.